1. Field of the Invention
The present invention relates to a cool air feeding system for refrigerators and, more particularly, to a system which feeds cool air to a refrigerator compartment using a duct or the like.
2. Discussion of Related Art
As illustrated in FIG. 1, a conventional cool air feeding system for refrigerators has a duct 2 installed on the rear wall of a refrigerator compartment. The inner space of the refrigerator compartment is divided into top, intermediate and lowest sections a, b and c by shelves. The refrigerator compartment has a plurality of cool air exhaling openings 3 for exhaling cool air to the top, intermediate and lowest sections respectively.
When operating the refrigerator, the cool air inhaled into the duct 2 from the freezer compartment is fed to the refrigerator compartment through the cool air exhaling openings 3 all having the same shape and size. But, since the same quantity of cool air is always fed to each part of the refrigerator compartment, if the foods stored in each shelf are not distributed equally and the kind and temperature of foods are different one another, disproportion in temperature is generated.
More cool air should be fed into the parts storing more foods and/or high temperature foods than into the other parts. But, in the conventional refrigerator, only a given quantity of cool air is fed into each part so that the foods stored may be over-cooled or under-cooled.
As illustrated in FIGS. 2 and 3, the conventional cool air feeding system may have a fan(not shown) for forcibly ventilating cool air into the freezer compartment 21, a duct and a plurality of shelves 23 installed on the rear wall of the refrigerator compartment 22 to guide and feed cool air into the refrigerator compartment.
As illustrated in FIG. 3, the duct 24 has a cool air inlet 25 for inhaling cool air and a cool air exhaling openings 26 for exhaling the inhaled cool air to the refrigerator compartment. Cool air exhaling openings 26 are also installed on a control box 27 disposed on the front part of the duct to thereby communicate with the cool air exhaling openings of the duct.
Therefore, the cool air inhaled in the cool air inlet 25 of the duct 24 is exhaled through the cool air exhaling openings 26 to each shelf 23 installed in the refrigerator compartment 22 to thereby cool the foods put on the shelf.
But, since the cool air exhaling openings 26 for exhaling cool air into the refrigerator compartment 26 are always fixed on the predetermined positions, they result in disproportion in temperature on each shelf 23. The parts of each shelf 23 in the vicinity of the cool air exhaling openings 26 are over-cooled so that the foods stored therein may freeze. On the contrary, the parts far away from the cool air exhaling openings 26 are not cooled so that the foods stored therein may spoil.
Also, disproportion in the temperature distribution increases power consumption.
FIGS. 4 to 7 show another example of the conventional cool air feeding system. The cool air feeding system, different from the one illustrated in FIGS. 1 to 3, extends into the lower side of the shelf. FIG. 4 is a front view of the refrigerator. As illustrated in FIG. 4, the reference numeral 31 designates a main body, 32 a freezer compartment, 33 a refrigerator compartment, 34 a vegetable box, 35 a freezer compartment door and 36 a refrigerator compartment door. As illustrated in FIGS. 6 and 7, the cool air feeding system includes a duct 41 installed on the rear of the refrigerator compartment 33, a plurality of cool air exhaling openings 41a formed on the duct, the cool air exhaling openings being spaced apart from one another, guide grooves 33a each formed on the inner side walls of the refrigerator compartment 33, and shelves 42 slidably combined with the guide grooves to distribute the cool air exhaled through the cool air exhaling openings 41a into the refrigerator compartment 33. Multi-story shelves 42 are displacably installed in the refrigerator compartment 33.
The shelf 42 includes a base 43 formed like a plate to support the stores on its upper surface, a duct 44 fixed on the central portion of the lower surface of the base 43 back and forth, a plurality of cool air exhaling openings 44a formed on the lower and lateral sides of the duct 44, and a cool air inhaling guide 45 formed on the rear end of the duct 44 to be thereby connected to the cool air exhaling openings 41a of the shelf 42. The duct 44 is fixed on the base 43 using the methods of adhering, interference fitting and high-frequency welding.
Therefore, when the shelf is pushed into the guide groove 43a formed on the inner lateral sides of the refrigerator compartment 33, the cool air inhaling guide 45 of the shelf 42 is connected to the cool air exhaling openings 41a of the duct 41. The cool air descended along the duct 41 is inhaled into the duct 44 through the cool air inhaling guide 45 of the shelf 42. The cool air inhaled moves along the duct 44 and exhales through the cool air exhaling openings 44a formed on the lower and lateral sides of the duct 44.
However, since the cool air feeding system like above has a structure that the duct 44 is fixed on the central portion of the lower surface of the shelf 42, the exhaling direction of the cool air towards the cool air exhaling openings 44a is limited. As a result, the foods stored in the edge of the refrigerator compartment or in the door can not be effectively cooled.